U.S. patent number 5,512,071 [Application Number 08/202,066] was granted by the patent office on 1996-04-30 for water soluble blast media containing surfactant.
This patent grant is currently assigned to Church & Dwight Co., Inc.. Invention is credited to Keith A. Jones, Amy L. Joseph, Anthony E. Winston, Benny S. Yam.
United States Patent |
5,512,071 |
Yam , et al. |
April 30, 1996 |
Water soluble blast media containing surfactant
Abstract
A blast media for stripping contaminants from a solid surface
comprises water soluble abrasive particles and a surfactant which
reduces the amount of water soluble residues of blast media
remaining on the targeted surface and which enables any residues
which remain to be readily removed by fresh water.
Inventors: |
Yam; Benny S. (Holmdel, NJ),
Joseph; Amy L. (Hopewell, NJ), Winston; Anthony E. (East
Brunswick, NJ), Jones; Keith A. (Yardley, PA) |
Assignee: |
Church & Dwight Co., Inc.
(Princeton, NJ)
|
Family
ID: |
21721978 |
Appl.
No.: |
08/202,066 |
Filed: |
February 25, 1994 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
6658 |
Jan 21, 1993 |
5316587 |
|
|
|
Current U.S.
Class: |
51/307; 134/7;
451/36; 451/38; 451/39; 451/40; 51/308; 510/201; 510/202; 510/240;
510/395 |
Current CPC
Class: |
B08B
7/00 (20130101); B24C 1/003 (20130101); B24C
1/086 (20130101); B24C 11/00 (20130101); B24C
11/005 (20130101); C01D 7/00 (20130101); C11D
17/0013 (20130101) |
Current International
Class: |
B08B
7/00 (20060101); B24C 11/00 (20060101); B24C
1/00 (20060101); C01D 7/00 (20060101); C11D
17/00 (20060101); C09C 001/68 () |
Field of
Search: |
;134/7
;51/317,319,320,304,306,307,308 ;252/174.14,174.21,116
;451/36,37,38,39,40 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
Advertisement--"Please Your Toughest Customer, Armex.RTM. Blast
Media, Accustrip System.TM., .COPYRGT.1992", Church & Dwight
Co., Ltd..
|
Primary Examiner: Lacey; David L.
Assistant Examiner: Vincent; Sean
Attorney, Agent or Firm: Depaoli & Frenkel
Parent Case Text
This application is a division of application Ser. No. 08/006,658,
filed Jan. 21, 1993, now U.S. Pat. No. 5,316,587.
Claims
What is claimed is:
1. A particulate blast media for stripping contaminants from a
solid surface consisting essentially of water soluble abrasive
particles having an average size of from about 50 to 1000 microns
in diameter and 0.05 to 3 wt. % relative to the amount of said
abrasive particles of a surfactant, wherein the amount of abrasive
particles above 1,000 microns does not exceed about 1% of the
abrasive particles.
2. The blast media of claim 1 wherein said water soluble abrasive
particles are sodium bicarbonate.
3. The blast media of claim 1 wherein said surfactant is a
solid.
4. The blast media of claim 1 wherein said surfactant is a
liquid.
5. The blast media of claim 1 wherein said surfactant is an anionic
surfactant.
6. The blast media of claim 5 wherein said surfactant is a
solid.
7. The blast media of claim 5 wherein said surfactant is selected
from the group consisting of sodium, potassium and ethanol amine
salts of N-lauroyl, N-myristoyl or N-palmitoyl sarcosinate.
8. The blast media of claim 4 wherein said liquid surfactant is
coated onto said abrasive particles.
9. The blast media of claim 4 further including a carrier particle
and wherein said liquid surfactant is coated onto said carrier
particles.
10. The blast media of claim 1 further including a flow aid.
11. The blast media of claim 10 wherein said flow aid is selected
from the group consisting of hydrophilic silica, hydrophobic
silica, hydrophobic polysiloxane and mixtures thereof.
12. The blast media of claim 1 wherein said surfactant is
nonionic.
13. The blast media of claim 1 wherein said surfactant comprises a
mixture of different surfactants.
14. The blast media of claim 13 wherein said mixture comprises a
mixture of an anionic surfactant and a nonionic surfactant.
15. The blast media of claim 1 wherein said surfactant comprises
N-alkyl-2-pyrrolidones.
16. The blast media of claim 1 wherein said surfactant comprises
polycarboxylated ethylene oxide condensates of fatty alcohols.
17. The blast media of claim 1 wherein said surfactant is an
ethoxylated long chain alcohol.
18. The blast media of claim 2 wherein said surfactant is an
ethoxylated long chain alcohol.
19. A particulate blast media for stripping contaminants from a
solid surface consisting essentially of water soluble abrasive
particles having an average size of from about 50 to 1,000 microns
in diameter and an anionic surfactant, wherein the amount of
abrasive particles above 1,000 microns does not exceed about 1% of
the abrasive particles.
20. The blast media of claim 19 wherein said anionic surfactant is
a solid.
21. The blast media of claim 19 wherein said anionic surfactant is
selected from the group consisting of sodium, potassium and ethanol
amine salts of N-lauroyl, N-myristoyl or N-palmitoyl
sarcosinate.
22. A particulate blast media for stripping contaminants from a
solid surface consisting essentially of water soluble abrasive
particles having an average size of from about 50 to 1,000 microns
in diameter and a mixture of an anionic surfactant and a nonionic
surfactant, wherein the amount of said abrasive particles above
1,000 microns does not exceed about 1% of the abrasive particles.
Description
FIELD OF THE INVENTION
The present invention relates to improvements in blast media
utilized to remove adherent material such as paint, scale, dirt,
grease and the like from solid surfaces. In particular, the present
invention is directed to water soluble abrasive blast media which
has incorporated therein a surfactant so that residues of the blast
media remaining on the targeted surface can be minimized and
readily removed.
DESCRIPTION OF THE PRIOR ART
In order to clean a solid surface so that such surface can again be
coated such as, for example, to preserve metal against
deterioration, remove graffiti from stone or simply to degrease or
remove dirt from a solid surface, it has become common practice to
use an abrasive blasting technique wherein abrasive particles are
propelled by a high pressure fluid against the solid surface in
order to dislodge previously applied coatings, scale, dirt, grease
or other contaminants. Various abrasive blasting techniques have
been utilized to remove coatings, grease and the like from solid
surfaces. Thus, blasting techniques comprising dry blasting which
involves directing the abrasive particles to a surface by means of
pressurized air typically ranging from 30 to 150 psi, wet blasting
in which the abrasive blast media is directed to the surface by a
highly pressurized stream of water typically 3,000 psi and above,
multi-step processes comprising dry or wet blasting and a
mechanical technique such as sanding, chipping, etc. and a single
step process in which both air and water are utilized either in
combination at high pressures to propel the abrasive blast media to
the surface as disclosed in U.S. Pat. No. 4,817,342, or in
combination with relatively low pressure water used as a dust
control agent or to control substrate damage have been used. Water
for dust control has been mixed with the air either internally in
the blast nozzle or at the targeted surface to be cleaned and such
latter process, although primarily a dry blasting technique, is
considered wet blasting inasmuch as media recovery and clean up is
substantially different from that utilized in a purely dry blasting
operation.
The blast media or abrasive particles most widely used for blasting
surfaces to remove adherent material therefrom is sand. Sand is a
hard abrasive which is very useful in removing adherent materials
such as paint, scale and other materials from metal surfaces such
as steel. While sand is a most useful abrasive for each type of
blasting technique, there are disadvantages in using sand as a
blast media. For one, sand, i.e., crystalline silica, is friable
and upon hitting a metal surface will break into minute particles
which are small enough to enter the lungs. These minute silica
particles pose a substantial health hazard. Additionally, much
effort is needed to remove the sand from the surrounding area after
completion of blasting. Still another disadvantage is the hardness
of sand itself. Thus, sand cannot readily be used as an abrasive to
remove coatings from relatively soft metals such as aluminum or any
other soft substrate such as plastic, plastic composite structures,
concrete or wood, as such relatively soft substrates can be
excessively damaged by the abrasiveness of sand. Moreover, sand
cannot be used around moving parts of machinery inasmuch as the
sand particles can enter bearing surfaces and the like.
An alternative to sand as a blast media, particularly, for removing
adherent coatings from relatively soft substrates such as softer
metals as aluminum, composite surfaces, plastics, concrete and the
like is sodium bicarbonate. While sodium bicarbonate is softer than
sand, it is sufficiently hard to remove coatings from aluminum
surfaces and as well remove other coatings including paint, dirt,
and grease from non-metallic surfaces without harming the substrate
surface. Sodium bicarbonate is not harmful to the environment and
is most advantageously water soluble such that the particles which
remain subsequent to blasting can be simply washed away without
yielding environmental harm. Since sodium bicarbonate is water
soluble and is benign to the environment, this particular blast
media has also found increasing use in removing coatings and in
cleaning dirt, grease and oil and the like from harder surfaces as
well including steel and interior surfaces such as those which
contact food such as in environments of food processing or
handling.
Sodium bicarbonate is also a friable abrasive and, like sand, will
form a considerable amount of dust during the blast cleaning
process. To control the dust formed by the sodium bicarbonate blast
media as it contacts the targeted surface, water is included in the
pressurized fluid carrier medium. Thus, water can be used as the
carrier fluid or, more preferably, injected into a pressurized air
stream which carries the blast media from the blast nozzle to the
targeted surface. Water as a means to control dust has been mixed
with the air stream internally in the blast nozzle or into the air
stream externally of the nozzle. The addition of water to the
pressurized air stream has been very effective in controlling dust
formed by the sodium bicarbonate blast media. One disadvantageous
result, however, of utilizing water to control the dust formed by
the sodium bicarbonate blast media is that a residue of the water
soluble sodium bicarbonate, flow aid or even calcium carbonate
formed by reaction of water-hardness ions with the bicarbonate
remains on the substrate surface. Even after rinsing the substrate
with water, this residue can remain leaving an unsightly film on
the cleaned surface.
Accordingly, it is the primary objective of the present invention
to make improvements in water soluble blast media so as to reduce
the residues of the media which remain on the targeted surface
subsequent to blasting and to render any residue which remains
readily removable.
Another object of the present invention is to provide an improved
process for blast cleaning a targeted surface with a water soluble
abrasive blast media which does not leave residue on the targeted
surface.
SUMMARY OF THE INVENTION
The above objects of the present invention are achieved by
incorporating with a water soluble blast media a small amount of a
surfactant. The surfactant can be incorporated with the blast media
either by mixing the surfactant with the solid particles of blast
media or by incorporating the surfactant in the water stream which
is utilized either as the carrier fluid for the blast media or
added to a pressurized air stream for the purpose of dust control.
The addition of the surfactant reduces the residues of the water
soluble media which remain on the targeted surface and any residue
which does remain can be easily removed by rinsing with fresh
water. The surfactant appears to lower the surface tension of the
water droplets containing dissolved media and attached to the
substrate surface causing the droplets to be readily washed from
the surface before the solubilized media can dry. The blast
cleaning process is not adversely affected by the addition of the
surfactant and, in fact, may enhance the cleaning efficiency of the
blast media to strip contaminants from a substrate in view of the
detergent action of the surfactant.
DETAILED DESCRIPTION OF THE INVENTION
The blast media to be utilized are water soluble and, typically
will be in the form of a powder containing substantially singular
abrasive particles have an average size range of from about 10 to
1,000 microns in diameter. Preferably, the blast media will
comprise abrasive particles having an average size of from about
50-500 microns and wherein the amount of particles above 1,000
microns does not exceed about 1% of the total media. Water soluble
blast media are advantageous since such blast media can be readily
disposed of by a water stream, are readily separated from the
insoluble paints and resins which have been stripped to facilitate
waste disposal, and since most water soluble blast media are
relatively soft, i.e., Mohs hardness less than 3.0, such media can
be utilized to remove coatings, grease, dirt and the like from a
variety of substrates including relatively soft metals such as
aluminum as well as plastic, ceramic, concrete, wood and composites
of such materials. Water soluble blast media having a Mohs hardness
of less than 5.0 are generally useful in this invention, in
particular, for cleaning softer substrates. Non-limiting examples
of water soluble blast media which can be utilized include the
alkali metal and alkaline earth metal salts such as the chlorides,
chlorates, carbonates, bicarbonates, sulfates, silicates, the
hydrates of the above, etc. The preferred blast media are the
alkali metal salts and, in particular, the sodium and potassium
carbonates, bicarbonates and sulfates. The most preferred blast
media are the alkali metal bicarbonates as exemplified by sodium
bicarbonate. Also preferably useful are sodium sesquicarbonate,
natural sodium sesquicarbonate known as trona, sodium bicarbonate,
sodium carbonate, potassium carbonate, potassium bicarbonate,
sodium chloride and sodium sulfate which is described in commonly
assigned U.S. Pat. No. 5,112,406. It is important to note that by
water soluble is not meant completely water soluble as some salts
and natural minerals such as trona may contain minor amounts of
insoluble materials. For example, trona which is a natural sodium
sesquicarbonate may contain up to 10 wt. % of insolubles. Thus, by
water soluble is meant to include those materials which are
substantially soluble in water and sufficiently soluble to leave a
water soluble residue on a targeted surface.
To reduce residues of the blast media from remaining on the
substrate surface, the blast media of the present invention has a
surfactant incorporated therein. The surfactant which may be
utilized can be anionic, nonionic or amphoteric in nature or
mixtures of the various types of surfactant can be used.
Anionic surfactants appear to best reduce the residue formation of
water soluble blast media components. Moreover, since most of the
anionic surfactants are solids, such surfactants can be simply
added as is to the blast media without adverse caking and
agglomeration of blast media particles. Examples of suitable
anionic surfactants are water-soluble salts of the higher alkyl
sulfates, such as sodium lauryl sulfate or other suitable alkyl
sulfates having 8 to 18 carbon atoms in the alkyl group,
water-soluble salts of higher fatty acid monoglyceride
monosulfates, such as the sodium salt of the monosulfated
monoglyceride of hydrogenated coconut oil fatty acids, alkyl aryl
sulfonates such as sodium dodecyl benzene sulfonate, higher alkyl
sulfoacetates, higher fatty acid esters of 1,2-dihydroxy propane
sulfonate, and the substantially saturated higher aliphatic acyl
amides of lower aliphatic amino carboxylic acid compounds, such as
those having 12 to 16 carbons in the fatty acid, alkyl or acyl
radicals, and the like. Examples of the last mentioned amides are
N-lauroyl sarcosinate, and the sodium, potassium, and ethanolamine
salts of N-lauroyl, N-myristoyl, or N-palmitoyl sarcosinate sold by
W. R. Grace under the tradename "Hamposyl". Also effective are
polycarboxylated ethylene oxide condensates of fatty alcohols
manufactured by Olin under the tradename of "Polytergent CS-1".
Amphoteric surfactants are a well known class of surfactants which
includes the alkyl beta-iminodipropionates RN(C.sub.2 H.sub.4
COOM).sub.2 and the alkyl beta-aminopropionates RNHCH.sub.4 COOM
where the alkyl group R contains 8 to 18 carbon atoms in both
formulae and M is a salt-forming cation such as the sodium ion.
Further examples are the long chain imidazole derivatives, for
example, the di-sodium salt of
lauroyl-cycloimidinium-1-ethoxy-ethionic acid-2-ethionic acid, and
the substituted betaines such as alkyl dimethyl ammonio acetates
where the alkyl group contains 12 to 18 carbon atoms.
N-alkyl-2-pyrrolidones which are highly polar apiotic solvents, are
also surface active and can be used. "Surfadone LP-100" from
International Specialty Products has been found particularly
useful.
Suitable non-ionic surfactants include the
polyoxyethylene-polyoxypropylene condensates, which are sold by
BASF under the tradename "Pluronic", polyoxyethylene condensates of
alkyl phenols; polyoxyethylene condensates of aliphatic
alcohols/ethylene oxide condensates having from 1 to 30 moles of
ethylene oxide per mole of coconut alcohol; ethoxylated long chain
alcohols sold by Shell Chemical Co. under the tradename "Neodol",
polyoxyethylene condensates of sorbitan fatty acids, alkanolamides,
such as the monoalkoanolamides, dialkanolamides and the ethoxylated
alkanolamides, for example coconut monoethanolamide, lauric
isopropanolamide and lauric diethanolamide; and amine oxides for
example dodecyldimethylamine oxide.
The surfactant of the present invention can be incorporated into
the water soluble blast media in a variety of ways. If solid, the
surfactant can be mixed as is with the abrasive blast media
particles. This is preferred and it has been found that the most
useful surfactants for reducing residue formation are anionic
surfactants which are mostly solid materials.
If the surfactant is liquid, the surfactant can be sprayed directly
onto the blast media particles. While this method is the most
direct way of incorporating the surfactant, the flow of the blast
media through the metering means which meters the amount of
abrasive particles into the fluid carrier stream may be adversely
affected by incorporating the surfactant in this manner. Thus, the
very fine particles of blast media may agglomerate and otherwise
cake or bride together and render particle flow through a metering
device difficult. Alternatively, the liquid surfactant can be
sprayed onto the blast media particles, the coated blast media
particles compacted and the compacted product which is formed
regranulated into a surfactant-containing solid. Compacting may be
performed by applying pressure to the surfactant-coated abrasive
particles such as by continuously admitting the coated abrasive
particles to a zone where the coated particles are subjected to
pressure between two rolls running oppositely with respect to each
other. A preferred means of compacting is by a roller compactor,
wherein the particles are subjected to pressure between two rolls
under an adjustable compacting pressure. An especially preferred
compactor is the Fitzpatrick Co. "Chilsonater" roll compactor. The
gap between the rolls, the amount of raw materials introduced to
such a roll compactor and the compacting pressure can be adjusted
to produce cohesive sheets or pellets of desired density and
hardness. The sheets or pellets are then regranulated by any
suitable granulating or crushing means. Preferably, the compacted
sheets, pellets and the like are fed through a sieve crusher to
force the compacted material through a sieve with meshes of a given
size determining the particle size of the final product. Screening,
if desired, can be performed by any suitable screening device.
Still further, the surfactant can be sprayed directly onto the
abrasive blast media particles and the surfactant-coated particles
then dusted with a very finely divided material to reduce the
caking and bridging between the abrasive particles. Thus, finely
divided fume silica, silicates such as clays, talc, mica,
diatomaceous earth and metal silicates such as aluminosilicates
including zeolites may be used for dusting the liquid
surfactant-coated abrasive. Obviously, the addition of a
significant amount of water insoluble additives reduces the
advantages of the water solubility of the abrasive blast media with
respect to disposal. Thus, the amount of dusting agent should be
minimized. Inasmuch as the amount of surfactant to be included is
minute, likewise the amount of the dusting agent required to
maintain free-flow of the blast media should also be minimal.
Still another method of incorporating the surfactant in the blast
media is to apply the surfactant to solid carrier particles similar
to those described above. Thus, fume silica, various silicates can
be utilized as the carrier particles including clays such as kaolin
clay, talc, mica, aluminosilicates such as zeolites, as well as
water insoluble carbonates, sulfates, etc. Again, the amount of
water insoluble materials should be minimized so as to not
adversely affect the advantages of the water soluble blast
media.
Further, the surfactant can be added to any flow aids which are
normally contained in blast media compositions by coating such
materials prior to incorporation thereof with the abrasive
particles. Such flow aids reduce caking of the water soluble blast
media and can include the carrier materials described above. Most
preferably, the flow aid is a hydrophilic or hydrophobic silica,
hydrophobic polysiloxane or mixture of such materials. These flow
aids are typically added in amounts of 0.05 to 20%, preferably
about 0.1 to 0.5% by weight relative to the total of abrasive
particles. In fact, it has been found that the residues from the
water soluble media which are formed are somewhat increased when
the blast media composition contains a flow aid. Hydrophobic
silica, unlike known hydrophilic silicas, is substantially free of
non-hydrogen bonded silanol group and absorbed water. One preferred
hydrophobic silica which may be utilized in the blasting media
hereof is Aerosil R 972, a product which is available from DeGussa
AG. This material is a pure coagulated silicon dioxide aerosol, in
which about 75% of the silanol groups on the surface thereof are
chemically reacted with dimethyldichlorosilane, the resulting
product having about 0.7 mmol of chemically combined methyl groups
per 100 m.sup.2 of surface area and containing about 1% carbon. Its
particles vary in diameter from about 10 to 40 nanometers and have
a specific surface area of about 110 m.sup.2 /gram. It may be
prepared by flame hydrolysis of a hydrophilic silica as more fully
described in Angew. Chem., 72, 744 (1960); F-pS 1,368,765; and
DT-AS 1,163,784. Further details respecting such material are
contained in the technical bulletin entitled "Basic Characteristics
and Applications of AEROSIL", DeGussa A. G., August 1986. The
hydrophobic silica particles are admixed with the abrasive blasting
media in the proportion of at least about 0.1 and up to about 1.0%
by weight thereof. Another hydrophobic silica is Quso, marketed by
DeGussa A. G.
Hydrophobic polysiloxanes, preferably non-halogenated
polysiloxanes, suitable for use in the blasting media hereof are
commercially marketed by Dow Corning and General Electric.
An alternative to adding the surfactant to any of the solid
materials which form the blast media is to add the surfactant to
the water which is utilized as the primary fluid carrier medium or
as a dust control agent. Thus, the surfactant can be added at the
supply of water or can be added to the water stream at the blast
nozzle. By incorporating the surfactant into the water stream, the
disadvantages of adding additional water insoluble materials to the
blast media is avoided and so is the agglomerating and caking,
bridging and restriction to flow of the blast media avoided.
Regardless of the method by which the surfactant is added to the
blast media, it has been found that the amount of residues which
remain on the target surface subsequent to blasting are drastically
reduced upon the addition of the surfactant and any residues which
do remain can be easily washed off with fresh water.
The amount of surfactant needed to provide reduced residue content
and easily rinsed residues is extremely small in most cases and,
thus, will range from about finite levels to about 3 wt. %,
preferably about 0.05 to about 1 wt. %, and, more preferably, from
about 0.05 to 0.5 wt. % of the abrasive blast media particles. As
stated above, it has further been found that the addition of the
surfactant can actually aid in removing any dirt, grease or oil
from the substrate. Nonionic surfactants appear to best provide the
additional detersive action. Thus, it may be possible to provide
several kinds of surfactants with the blast media including those
most readily able to reduce residue formation such as anionic
surfactants and those capable of enhancing the removal of dirt,
grease or oil from the substrate. The surfactant advantageously
solubilizes the dirt and grease allowing easier clean up and
reduces the deflection of dirt from one surface to another.
The blast media of the present invention as constituted from the
water soluble abrasive particles and surfactant as described above
are useful for efficient cleaning or decoating of sensitive metals
such as aluminum or aluminum alloys, magnesium, or composite
substrates, such as utilized on exterior aircraft surfaces,
masonry, stucco, plaster, wood or plastics. Hard steel surfaces can
also be cleaned. Such blast media are preferably applied in
commercial pressurized water and, more preferably, compressed air
streams which contain water either added at the blast nozzle or
externally therefrom so as to control dust formation. Blasting
equipment for the blast media of the present invention are
commercially available. The blast media of flow rates through the
blast nozzle typically range from about 0.5 to 15, desirably from
about 1.0 to 10.0 lbs per minute and under air pressures from 10 to
100 psi and water pressures for dust control typically ranging from
about 10 psi and above.
As indicated above and as more fully documented below, in
accordance with the present invention, it has been found that the
blast media of the present invention do not leave a substantial
amount of residue on the targeted surface and that any residue
which remains can be easily removed by the application of fresh
water. Thus, the blast media of the present invention can be
readily employed in commercial blasting operations for removing
coatings from relatively soft surfaces.
The following examples are for the purpose of illustrating the
invention and are not to be construed as strictly limiting the
invention to only the illustrated embodiments.
EXAMPLE 1
Aqueous saturated solutions each containing a 15 wt. % of a blast
media composition were prepared. The compositions are set forth in
Table 1. Compositions A and G represent controls. Glass micro
slides were submerged in the saturated solutions for two minutes.
The slides were then rinsed with fresh water using a wash bottle
for 10 seconds. The rinsed slides were dried at ambient conditions
overnight. The amount of film on the slides was observed under
light and quantified by naked eye. Results are shown in Table
1.
It can be seen that the surfactants tested greatly reduced the
residues formed by the control compositions. Anionic, amphoteric
and nonionic surfactants were effective in reducing the residues on
the glass surface.
TABLE 1
__________________________________________________________________________
Blast Media Compositions (wt. %) A B C D E F G
__________________________________________________________________________
Sodium Bicarbonate 99.75 99.70 99.65 99.65 99.65 99.65 100.0 Sylox
.RTM. 15.sup.1 0.25 0.25 0.25 0.25 0.25 0.25 -- Hamposyl .RTM. L-95
-- 0.05 -- -- -- -- -- Surfadone .RTM. LP-100 -- -- 0.20 -- -- --
-- Poly-Tergent .RTM. CS-1 -- -- -- 0.10 -- -- -- Neodol .RTM. 91-6
-- -- -- -- 0.10 -- Neodol .RTM. 25-12 -- -- -- -- -- 0.10 --
Amount on film observed Heavy None- None- None- Sl. Sl. Mod.- on
rinsed glass slide V.Sl..sup.2 V.Sl. V.Sl. Heavy
__________________________________________________________________________
.sup.1 Hydrophilic silica flow aid .sup.2 V.Sl. = Very slight
EXAMPLE 2
Clear safety glass panels (15 in..times.15 in.) were blasted with
various blast media using the Accustrip.TM. System at the following
operating conditions: 60 psi blast air pressure, 4 lbs/min. media
flow rate, and 0.5 gpm water flow rate. The glass slides were then
rinsed with fresh water for 30 seconds. The rinsed panels were
dried overnight. The amount of film of the glass panels was
observed as in Example 1. Blast media compositions and results of
testing are set forth in Table 2.
TABLE 2 ______________________________________ Blast Media
Compositions (%) A B C ______________________________________
Sodium Bicarbonate 99.75 99.50 100.0 Sylox .RTM. 15 0.25 0.25 --
Hamposyl .RTM. L-95 -- 0.25 -- Amount of film Heavy V. slight
Moderate observed on rinsed glass slide
______________________________________
* * * * *